to Dr. van Breemen by the manufacturer to support the development of ultrafiltration mass spectrometry as a tool for drug discovery and development. To prevent delays when demands for the QTOF2 become great, this instrument may be used to support peptide sequencing and characterization as well. Micromass Quattro II triple quadrupole mass spectrometer. Installed during 1997 and purchased with an NIH shared instrument grant (P.I. Dr. van Breemen), this triple quadrupole mass spectrometer is equipped with a Water 2690 analytical HPLC system, electrospray ionization, atmospheric pressure chemical ionization (APCI), and MS-MS with CID. It is used primarily for structural analysis of natural products and drug metabolites or for quantitative analysis of therapeutic agents and drug metabolites. Thermo Electron (Finnigan) TSQ Quantum triple quadrupole mass spectrometer. Purchased in 2002 to help with the backlog of samples awaiting quantitative analysis using LC-MS-MS, this instrument is equipped with a Surveyor analytical HPLC system, 282